You’ve probably seen Keenan Cahill’s other videos on YouTube, but his new cover of Katy Perry’s ‘Last Friday Night (T.G.I.F.)’ is epic! Dianna Agron, Harry Shum Jr., Darren Criss and Jenna Ushkowitz are all backup dancers!

Throughout the last year, Keenan Cahill has become a major YouTube sensation known for his lip sync covers to today’s most popular songs. Even though the Illinois teen (who suffers from Maroteaux-Lamy syndrome) has had some pretty awesome A-list guest stars (ie: 50 Cent, David Guetta and more), we’re loving his latest video starring none other than Glee starsDianna Agron, Harry Shum Jr., Darren Criss and Jenna Ushkowitz as backup dancers!